chore: standardize the error message of a subet of unreachable! calls

src/ppu.rs

@@ -197,7 +197,7 @@ impl From<u8> for GrayShade {
             0b01 => GrayShade::LightGray,
             0b10 => GrayShade::DarkGray,
             0b11 => GrayShade::Black,
-            _ => unreachable!("{:#04X} is not a valid Shade of Gray", byte),
+            _ => unreachable!("{:#04X} is not a valid value for GrayShade", byte),
         }
     }
 }

src/sound.rs

@@ -96,7 +96,7 @@ impl From<u8> for FrequencyType {
         match byte {
             0b00 => Self::Counter,
             0b01 => Self::Consecutive,
-            _ => unreachable!("{} is not a valid number for FrequencyType"),
+            _ => unreachable!("{:#04X} is not a valid value for FrequencyType"),
         }
     }
 }
@@ -194,10 +194,7 @@ impl From<u8> for EnvelopeDirection {
         match byte {
             0b00 => Self::Decrease,
             0b01 => Self::Increase,
-            _ => unreachable!(
-                "{:#04X} is not a possible value for EnvelopeDirection",
-                byte
-            ),
+            _ => unreachable!("{:#04X} is not a valid value for EnvelopeDirection", byte),
         }
     }
 }
@@ -267,7 +264,7 @@ impl From<u8> for WavePattern {
             0b01 => Self::OneQuarter,
             0b10 => Self::OneHalf,
             0b11 => Self::ThreeQuarters,
-            _ => unreachable!("{:#04X} is not a valid value for a Sound Wave", byte),
+            _ => unreachable!("{:#04X} is not a valid value for WavePattern", byte),
         }
     }
 }

src/timer.rs

@@ -32,11 +32,11 @@ pub enum TimerSpeed {
 impl From<u8> for TimerSpeed {
     fn from(byte: u8) -> Self {
         match byte {
-            0x00 => Self::Freq4096Hz,
-            0x01 => Self::Freq262144Hz,
-            0x10 => Self::Freq65536Hz,
-            0x11 => Self::Freq16384Hz,
-            _ => unreachable!("{:04X} is not a valid representation of TimerSpeed", byte),
+            0b00 => Self::Freq4096Hz,
+            0b01 => Self::Freq262144Hz,
+            0b10 => Self::Freq65536Hz,
+            0b11 => Self::Freq16384Hz,
+            _ => unreachable!("{:#04X} is not a valid value for TimerSpeed", byte),
         }
     }
 }